Double mosaic screen



June 20, 1939. B. BARTELS I DOUBLE MOSAIC SCREEN Filed Jan. 9, 1937 W MO F INVENTOR BERNHARD BARTELS BY ATTORN EY Patented June 20, 1939 UNITED STATES PATENT OFFICE DOUBLE MOSAIG SCREEN tion of Germany Application January 9, 1937, Serial No. 119,723 In Germany December 24, 1935 Claims.

The invention relates broadly to mosaic screens which are used in television transmitters, and more particularly to that type of mosaic screen which is commonly called the grid screen 5 or the double mosaic.

Grid screens of the double mosaic type are in general comprised of a supporting metallic structure which is multi-apertured in form, that is to say, contains therein a considerable number of 1 interstices. Through each one of these apertures or interstices there is passed a conducting element, and on the surface of the conducting element which faces the optical View to be transmitted, there is deposited a photoelectric light ll sensitive material. The other end of the conductor faces the cathode ray generating apparatus and is subject to bombardment thereby in order to neutralize the charges formed by photoelectric emission. It is clear, therefore, that all m of these conductors in order to form discrete photoelectric units must be insulated from each other, and it is an object of this invention to provide a grid screen in which this is accomplished, and to provide a method of making such a screen 35 in a practicable fashion.

The invention will best be understood by reference to the drawing in which Fig. 1 shows a cross-section of the support member, and

80 Fig. 2 is a front view thereof.

Referring to the drawing in Fig. 1 I0 represents the bridges of metal between the interstices or apertures; ll represents the openings or apertures through which the conductors pass; and I2 represents the insulating layer which is provided for keeping the conducting elements electrically separate and discrete.

The method of forming the screen is as follows: the apertures H are filled with silver oxide in powder form or as a paste, the latter being obtainable by stirring the silver oxide in alcohol. The apertures having been filled, the silver oxide is heated to an appropriate temperature in order to reduce it to metallic silver, the temperature being in the neighborhood of 150 C. The oxygen thus liberated by the reducing process will oxidize the metal support, thus forming an insulating layer between the silver which now forms the conductor and the sieve-like support. A photoelectric material may be deposited on the faces of the silver conductors which are placed on the side of the screen which is to be submitted to the photoelectric effect of an optical image.

The above described method has particular ad- 66 vantages if there is used for the support a metal whose oxide is an electric insulator and if the insulating layer between the bridges l0 and the grid conductors is produced by oxidation of the surface of the bridges it] before the silver oxide is reduced, are placed in the apertures. In this case defects in the insulating layer formed by the first oxidation will be eliminated by the oxygen liberated due to the reduction of the silver oxide.

Referring to Fig. 2, there is shown a front view of the support member to bring out the relative positioning and shape of the support structure iii and the apertures ll.

What I claim is:

1. In a double mosaic screen for cathode ray tubes in which a photosensitive material is deposited on one face of a number of discrete conductors passed through apertures in a metallic support, the method of assembling said screen which comprises the steps of oxidizing the surface of the apertures of the support so as to form an insulating surface thereon, next filling the apertures with a metallic oxide, subsequently reducing the oxide, andfinally depositing photosensitive material on one face of the metal obtained by the reduction.

2. The process of fabricating mosaic electrodes wherein conductors are passed through the interstices of a metallic support member which comprises the steps of placing in the interstices of the metallic support member a metallic oxide, reducing said metallic oxide and simultaneously oxidizing the inner surface of said interstices with the nascent oxygen liberated by said reduction, and photo-sensitizing one face of the reduced metallic oxide.

3. The process of fabricating mosaic electrodes wherein conductors are passed through the interstices of a metallic support member which comprises the steps of placing in the interstices of the metallic support member a metallic oxide, reducing said metallic oxide and simultaneously oxidizing the inner surface of said interstices with the nascent oxygen liberated by said reduction, and depositing a layer of photosensitive material on one face of each of the metal conductors formed by the reduction.

4. The process of fabricating mosaic electrodes wherein conductors are passed through the interstices of a metallic support member which comprises the steps of placing in the interstices of the metallic support member a silver oxide, reducing said silver oxide and simultaneously oxidizing the inner surface of said interstices with the nascent oxygen liberated by said ing said silver oxide and simultaneously oxidizing the inner surface of saidjnterstices with the nascent oxygen liberated by said reduction, and depositing a layer of photosensitive material on one face of each of the metal conductors formed 5 by the reduction.

BERNHARD BAR'I'ELS. 

